Navigation systems for supporting the driver of a motor vehicle have become more and more common in recent years and are part of the standard equipment of a new motor vehicle in many cases. In order for a navigation system to be able to calculate a route, an initial point and an endpoint, i.e., starting point and destination of a travel route, must be established. The starting point may typically correspond to the current position of the vehicle and is determinable via an automated positioning system or the starting position may be input by the user of the navigation system. The destination is typically always input. A destination is input into the navigation system by the user with the aid of an input routine which is implemented in a piece of software. Among other things, the input routine must have the characteristics of unambiguousness, operability, and technical feasibility.
Information about the destination is expected from the user in selecting the destination. This information is referred to as destination parameters. Examples for destination parameters include the name of the country, the name of the state, the name of the city, the name of the city district, the name of the street, and the house number. Additional destination parameters could be the ZIP code, the area code, and/or the phone number of the end subscriber.
Not all destination parameters provided in a navigation system need to be known to the system in order to unambiguously select a destination. The destination parameters requested from the user are different in different countries and depend on country-specific peculiarities. The indication of city, street, and house number is typically sufficient in the Federal Republic of Germany. This corresponds to the postal address and the user is generally able to provide this information. Only in cases of ambiguity, when, for example, multiple cities in different areas have the same name, should the system detect this and request additional information from the user, such as the first numbers of the ZIP code or a name of a city-district.
This approach is successful in the Federal Republic of Germany due to the fact that postal addressing and political zoning always match. It is a different picture in the United States of America, for example. A discrepancy of postal and political names for one and the same locality may occur there or streets may extend under the same name and consecutive house numbers over several localities. These cases result in the fact that the user may not know the exact name of the city where the destination is located. However, the user is in the position to specify the name of the street and the house number.
A travel destination is typically selected manually via an input device using characters or via spelling by voice input. Real typing via keys or clicking on, i.e., selecting, graphic icons is often possible. All destination parameters are presented individually and consecutively; for example, the name of the locality is specified first, followed by the name of the street and the house number.
However, the user is guided most of the time to consider the allowed names in such a way that erroneous inputs are preferably avoided. This is achieved by providing, at some points, the appropriate still possible continuation characters. Free writing is thus replaced by selecting from a concurrent selection set. This character input approach is referred to as “automatic spelling function” (ASF).
In conventional input routines, the sequence of the destination parameters may be varied during input. However, it is necessary in these routines that one destination parameter must be input completely and unambiguously before the next destination parameter can be selected. Also, the sequence of the parameters is usually not freely selectable but is rather predefined by the input routine. Such input routines actually do not permit a free selection, but offer only a plurality of sequences of the destination parameter selection which, however, is fixedly predefined.